Anadenanthera peregrina, also known as Yopo, Jopo, Cohoba, Parica or Calcium Tree, is a perennial tree of the Anadenanthera genus native to the Caribbean and South America.[1] It grows up to 20 m tall, having a horny bark. Its flowers are pale yellow to white and spherical. It is not listed as being a threatened species. It is an entheogen used in healing ceremonies and rituals. It is also a well known source of dietary calcium.

This plant is almost identical to that of a related tree, Anadenanthera colubrina, commonly known as Cebíl or Vilca. The beans of A. colubrina have a similar chemical makeup as Anadenanthera peregrina, with their primary constituent being 5-OH-DMT (bufotenin).

Archaeological evidence shows Anadenanthera beans have been used as hallucinogens for thousands of years. The oldest clear evidence of use comes from smoking pipes made of puma bone (Felis Concolor) found with Anadenanthera beans at Inca Cueva, a site in the northwest of Humahuaca in the Puna border of Jujuy Province, Argentina. The pipes were found to contain the hallucinogen DMT, one of the compounds found in Anadenanthera beans. Radiocarbon testing of the material gave a date of 2130 BC., suggesting Anadenanthera use as a hallucinogen is over 4000 years old.[10] Snuff trays and tubes similar to those commonly used for yopo were found in the central Peruvian coast dating back to 1200 BC., suggesting that insufflation of Anadenanthera beans is a more recent method of use.[11] Archaeological evidence of insufflation use within the period 500-1000 AD. in northern Chile has been reported.[12]

Yopo snuff is usually blown into the user's nostrils by another person through bamboo tubes or sometimes snuffed by the user using bird bone tubes. Blowing is more effective as this method allows more powder to enter the nose and is said to be less irritating. In some areas the unprocessed ground beans are snuffed or smoked producing a much weaker effect with stronger physical symptoms. Some tribes use yopo along with Banisteriopsis caapi to increase and prolong the visionary effects, creating an experience similar to that of ayahuasca.

To make the psychedelic snuff called yopo, the black beans from the bean pods of these trees are first toasted until the beans pop like popcorn breaking the bean's husk. The roasting process facilitates removal of the husk and makes the beans easier to grind into a powder. The bean's husk is usually removed because it is difficult to powderise and adds unnecessary volume. The bean is then ground with a mortar and pestle into a powder and mixed with a natural form of calcium hydroxide (lime) or calcium oxide (from certain types of ashes, calcined shells, etc.). This mix is then moistened to a consistency similar to breaddough, using a small amount of water. If calcium oxide is used, the water will react with it to form calcium hydroxide. Once moistened, it is kneaded into a ball for several minutes. After kneading, it is then left to sit for several hours to several days, depending on the local customs. During this period most of the excess calcium hydroxide reacts with the carbon dioxide in the air to form less caustic calcium carbonate (carbonatation).

Inhaling Yopo can cause considerable pain in nostrils. However, this pain usually subsides within minutes. Physical effects include tingling and numbness throughout the body and an increased heart rate. Hallucinatory effects follow as colours become more vivid and shapes appear to alter. The effects of Yopo intensify quickly but gradually fade and are replaced by nausea and general unease. Increased amounts of the substance induced may intensify and lengthen effects.

The beans have been found to contain up to 7.4% bufotenin.[13] At up to 7.4% (74 mg per gram) bufotenin, an effective 40 mg dose of insufflated bufotenin[13] requires little more than 0.5 grams of beans.

The intraperitonealLD50 of bufotenin is between 200–300 mg/kg (in rodents) with death occurring by respiratory arrest. The LD50 in rodents amounts to between 10,000 mg and 15,000 mg for a small 50 kg (110 lb) adult.[14] Based on the intraperitoneal LD50 for rodents, at 74 mg per gram, it would require approximately 135 grams of beans to reach the estimated LD50of bufotenin for a 50 kg (110 lb) adult. Human intravenous tests using bufotenin suggest the LD50 may be much lower in humans with subjects showing signs of peripheral toxicity (purple face, tachycardia, difficulty breathing, etc.) at doses as little as 8 mg in some subjects.[15] Free base bufotenin when insufflated, taken sublingually, orally, or intrarectally, elicits strong hallucinogenic effects with far less side effects.[13]

The effects of insufflated DMT and 5-MeO-DMT are relatively short acting, lasting about 1 hour, while the effects of insufflated yopo typically last 2–3 hours. Of the three main compounds present, only insufflated bufotenin lasts 2–3 hours. Claims[according to whom?] of Anadenanthera peregrina containing DMT and 5-MeO-DMT as their main active ingredients are based on rare cases where these compounds are found in larger quantities than bufotenin. Typical acid base extraction techniques utilizing strong bases such as sodium hydroxide solution will exclude bufotenin from the extraction, in favor of DMT and 5-MeO-DMT. It is believed[according to whom?] that such extractions have contributed to the misconception that bufotenin is a minor alkaloid in yopo. The majority of the extractions confirm[according to whom?] that bufotenin is primarily responsible for the effects of yopo with the other compounds usually appearing in quantities too small to produce noticeable effects in an average yopo dose of 5-10 grams.

The beans have been found to contain up to only 0.04% 5-MeO-DMT and 0.16% DMT.[13] The leaves and bark also contain small amounts of DMT, 5-MeO-DMT and related compounds.[16]

At up to 0.04% (0.4mg per gram) 5-MeO-DMT, an effective light 5mg dose of insufflated 5-MeO-DMT would require over 12 grams of beans. It would be extremely difficult to insufflate such a quantity, as tolerance would likely develop before the 12-gram nasal intake could be completed. Individual sensitivity to 5-MeO-DMT varies. It has been documented that the threshold dose in some individuals is as much as 10mg insufflated[17] requiring over 24 grams of beans for an effective dose of 5-MeO-DMT.

At up to 0.16% (1.6mg per gram) DMT, an effective 40mg dose of insufflated DMT would require 25 grams or more. It’s likely to be impossible[according to whom?] to insufflate the 25 grams of beans required to reach the active dose of DMT present in the beans. An extract of 25 grams of beans could contain up to 1,850mg of bufotenin, a potentially dangerous dose. With insufflated freebase bufotenin, the maximum published safe dose used has been 100mg.[13]

Unlike bufotenin, both DMT and 5-MeO-DMT are relatively unstable and begin to degrade rather quickly. Schultes and colleges (1977) examined a 120 year old bean collection and found 0.6% bufotenin with no DMT or 5-MeO-DMT present at all. They also examined a batch of beans that contained all three compounds when fresh, but found only bufotenin in the beans after only two years of storage.[14]

When taken orally by some tribes in South America, small amounts are often combined with alcoholic chichas (maize based beer).[14] Moderate doses are unpleasant, producing nausea and vomiting. The beans were a main ingredient in bilca tauri, an oral purge medicine used to induce ritual vomiting once a month.[14] Large amounts are not usually consumed orally; as many tribes believe oral use is dangerous.

Some South American tribes have been documented to use various bean preparations along with Banisteriopsis caapi, a herb containing MAOIs.[14] Typically Banisteriopsis caapi is chewed in the mouth while the Anadenanthera beans are snuffed or smoked.[14] Occasionally Banisteriopsis caapi is found mixed in with the snuff.[14] Moderate amounts of Banisteriopsis caapi will effectively double the potency of the Anadenanthera beans. Larger amounts of Banisteriopsis caapi will not only double the potency of Anadenanthera beans but also alter the quality of the experience, producing a more relaxed dreamy effect, with possible increased nausea. There are no well documented reports of the beans being used as a major component in ingestion of ayahuasca, a therapeutic tea made with Banisteriopsis caapi.